Stored Skim Milk Powder Suppresses Incretin Release from Intestinal Neuroendocrine Cells

Incretins have a crucial role for postprandial glucose management residing in glucagon-like-peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). The incretin role in glucose handling is estimated to 74%, and their absence or reduction being linked to severely impaired glucose control and diabetes. Dairy foods are crucial for adequate nutrition at young age, and with skim milk powder in infant formula, an optimal amount of nutrition is available. Skim milk powder after storage has however in experimental studies been found to reduce islet cell mass of pancreas with an unknown mechanism of action. The aim of this study is to investigate a potential effect of stored skim milk powder on incretin release from intestinal cells. Intestinal endocrine cells (STC-1 cells) were incubated with fresh and stored skim milk powder, the latter containing 70-fold higher amounts of Maillard reactants. Viability, proliferation and release of incretins were measured after 24 hours. Both viability and proliferation of the STC-1 cells decreased significantly during incubation with stored skim milk powder. The release of GLP-1 and GIP was suppressed in a dose-dependent way by stored skim milk powder compared to fresh milk powder. Incretin release from intestinal cells was suppressed by stored skim milk powder containing high amount of Maillard reactants. The clinical significance of this for development of diabetes and obesity awaits further studies.